class Calculator:
    def jiafa(self, a, b):
        return a + b

    def jianfa(self, a, b):
        return a - b

    def chengfa(self, a, b):
        return a * b

    def chufa(self, a, b):
        if b ==0:
            print("被除数不能为0")
        else:
            return a / b